2. Draw to lines in your notebook line the ones below. What is true about the lines?

3. THEY ARE PARALLEL. MARK THEM.

4. Draw a transversal. A transversal is a line that intersects two other lines.

5. Label the intersection points A & B.

6. Draw another transversal that intersects B.

7. What angles are equal in this picture? You do not have to write this down.

8. Write this down.  1   5 since they are corresponding angles.

9. Draw another transversal that intersect point B. What is a transversal again?

11. Which angle is congruent to  9? Why?

12. Which angle is congruent to  9? Why?

13.  9   11 since they are corresponding angles. Write this down.

14.  9   11 since they are corresponding angles. Mark this in your diagram.

15. Are there other angles that are congruent?

16.  15   16 because they are vertical angles.

17. What does this justify or prove? NCTMNCTM

18. THE SUM OF THE ANGLES IN A TRIANGLE ADD TO 180 

20. Website regarding triangles http://argyll.epsb.ca/jreed/math9/strand3/3103.htm http://www.ies.co.jp/math/java/geo/san180/san180.html Practice Problems: HW

22. Triangles in Architecture

23. New design for a building in London; has not been completed yet.

24. Hearst Tower in Manhattan, New York

25. Close up view of the Hearst Tower.

26. The inside of a dome.

27. Truss bridges use the triangle — a very stable shape — to distribute load forces.

28. Howrah Bridge spans over the Hooghly River in West Bengal, India.

29. The Little Belt Bridge also known as The Old Little Belt Bridge, is a truss bridge over the Little Belt strait in Denmark.

30. The pyramids of Giza in Cairo, Egypt

31. Unitarian Meeting House built by Frank Lloyd Wright in Madison, Wisconsin.